Based on Zhang’s security model, an improved pairing-free certificateless key agreement,CL-AKA random oracle model, was proposed. An ephemeral-secret query and three types of fresh oracles were further defined in the improved CL-AKA random oracle model to achieve the simulation of key-compromise impersonation, disclosure of ephemeral secrets and perfect forward secrecy. A CL-AKA protocol with strong security was proposed, costing only 9 scalar multiplications on the elliptic curve. The secure of the new protocol was proved in the improved model. The comparative analysis pointed out that the new protocol with strong security and low computing costs can be used to build secure mobile communication environment.
